apologies added details, ah I understand what you mean. I couldn’t find any, should I goto Mercedes directly? Anything else I could check to clarify if it is the regulator?
HiYou did not state if the headlights or other consumers of electricity were on when you read the 13.7 volts. When testing anything make sure all variables are the same so that you can distinguish differences. If any electrical consumers were on during your first test I would say that 13.7 @ idle is good.
I get 14.2 @ idle... no consumers.
I get 13.6 - 13.8... depending on the number & type of consumables @ idle.
I have a Brand New Bosch Alternator.
Okey dokey will have a clean of them, as due to a slight oil leak and bit of rust over the yearsGround Contacts: Clean where the Battery Cable meets the Fender, there is another from the Starter to the Bell Housing. I would also add a ground wire from the instrument cluster to the Fire Wall... this one is a big deal and probably does more to 'fix' instrument cluster issues than anything else. I'm speaking to mid 80(s) W123 Diesels yours may vary.
If I missed one guys... please chime in.
Cool! Ok mate will get cracking with the suggestions, thanks so much. Appreciated, will update with results on these.Why would someone only clean the grounds? Clean all of the battery connections.
I am assuming that the alternator on the gasser has the same alternator electrical connector.
Don't know how much room there is to do this on the gasser. When you remove the alternator electrical connector you will see that it can be taken apart.
I suspect what you are going to find is the are the wire connect to the brass connector and or the brass is corroded. Depending on what you find will determine your action.
While the electrical connector is out remove the voltage regulator and look inside at the metal sort of finger that makes contact with the voltage regulator if that is corroded it needs to be cleaned.
This is a pic a corroded contact finger
View attachment 2801419
Also look inside at the condition of the slip ring.
There is also a test using an electrical multi-meter (volt Ohm meter) that checks for AC current. One of the names for the test is a voltage ripple test.
What it is about is that you can appear to have good charging voltage but there is a diode issue that is putting out too much AC voltage.
Do a google image search and there are various videos on how to do it. Due to the type of plug-in electrical connector you limited to reading it over the 2 battery terminals. The main thing is you need to know what AC voltage to set the meter to.
There is also another test called the voltage bypass test that will tell you if your battery cables have too much resistance. Again, instructions on the internet buy doing a google image search.
I put in a different battery ground to chassis cable and found I got a whole other volt during charging afterwards
If your probe the disconnected alternator electrical connector with your voltmeter:
The 2 large slots on the alternator electrical connector should always have battery voltage. The single smaller slot should have no voltage when the key is off.
On the diesel when you turn the key on the voltage only drops about .3-.5 volts. I am not sure how much the voltage drops on a gasser due to the ignition and if it has an electric fuel pump.
Yeh I will do… ill keep an eye on it.Keep at it!!!
If you have a trickle charger you may want to keep that new battery fresh while you are not working on the car as you are draining the battery... even @ idle. It will not be long before you will start getting 12.2 and then 12.1 etc 'before start' unless the battery gets some charge.
I hate to say it... but, I smell a 'new alternator' in the not to distant future.
Cool will do, most eBay ones available for uk are from Germany. But will have a hunt around while I’m waiting to do other tests.Rebuilds are fine... they are around 200 (including a core charge) so you will get 50 or 60 back ... so, 140 to 150 range (with free shipping).
Shop around and get it from someone reliable like Pelican, ECS Tuning etc. Don't trust eBay Sellers.
OH! Get the 65amp Rebuild! Double OH! Sorry, Yer a BRIT! Still don't get it off eBay!
You can get alternators rebuilt at small places that do these and starter motors. Can be a great way of avoiding cheap shite parts.Cool will do, most eBay ones available for uk are from Germany. But will have a hunt around while I’m waiting to do other tests.